The influence of various culture parameters on the attachment of a rec
ombinant baculovirus to suspended insect cells was examined under norm
al culture conditions. These parameters included cell density, multipl
icity of infection, and composition of the cell growth medium. It was
found that the fractional rate of virus attachment was independent of
the multiplicity of infection but dependent on the cell density. A fir
st order mathematical model was used to simulate the adsorption kineti
cs and predict the efficiency of virus attachment under the various cu
lture conditions. This calculated efficiency of virus attachment was o
bserved to decrease at high cell densities, which was attributed to ce
ll clumping. It was also observed that virus attachment was more effic
ient in Sf900II serum free medium than it was in IPL-41 serum-suppleme
nted medium. This effect was attributed to the protein in serum which
may coat the cells and so inhibit adsorption. A general discussion rel
ating the observations made in-these experiments to the kinetics of re
combinant baculovirus adsorption to suspended insect cells is presente
d.